The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The present disclosure also relates to a nacelle for a turbine engine of an aircraft including an external structure concentrically covering at least one portion of such an inner structure.
An aircraft is driven by several turbine engines each housed in a nacelle also harboring an assembly of ancillary actuation devices related to its operation and ensuring various functions when the turbine engine is operating or at a standstill. These ancillary actuation devices notably comprise a mechanical system for actuating a thrust reverser.
A nacelle generally has a tubular structure along a longitudinal axis comprising an air intake upstream from the turbine engine, a middle section intended to surround a fan of the turbine engine, a downstream section harboring thrust reversal means and intended to surround the combustion chamber of the turbine engine. The tubular structure generally ends with an ejection nozzle, the outlet of which is located downstream from the turbine engine.
Modern nacelles are intended to house a dual flux turbine engine capable of generating via rotating blades of the fan a hot air flow (also called a <<primary flow>>) stemming from the combustion chamber of the turbine engine, and a cold air flow (<<secondary flow>>) which circulates outside the turbine engine through a ring shaped passage also called <<annular vein >>.
By the term of <<downstream>> is meant here the direction corresponding to the direction of the cold air flow penetrating the turbine engine. The term of <<upstream>> designates the opposite direction.
The annular vein is formed by an outer structure, a so-called Outer Fixed Structure (OFS) and a concentric inner structure, called an Inner Fixed Structure (IFS), surrounding the structure of the engine strictly speaking downstream from the fan. The inner and outer structures belong to the downstream section. The outer structure may include one or several sliding cowls along the longitudinal axis of the nacelle between a position allowing the exhaust of the reversed air flow and a position preventing such an exhaust.
Moreover, a plurality of sliding cowls is positioned in the downstream section and has a downstream side forming the ejection nozzle aiming at channeling the ejection of the cold air flow, designated hereafter by <<air flow>>. Each sliding cowl typically has a thrust reversal function. This nozzle provides the power required for propulsion by imparting speed to the ejection flows. This nozzle is associated with an actuation system either independent or not of that of the cowl allowing variation and optimization of the section of the annular vein according to the flight phase in which is found the aircraft.
Customarily, the variable nozzle is formed with mobile elements configured so as to allow a decrease in the ejection section of the airflow at the outlet of the annular vein. These mobile elements are generally actuated by control means.
However, such a variation of the ejection section of the airflow is quite complex to apply. Indeed, this assumes placement of mechanical parts or of an additional system at the sliding cowl. Further, this type of variable nozzle is not easily transposable to other types of nacelle either having or not thrust reversal means.
The present disclosure provides a nacelle, for which the ejection section of the airflow is variable by means which do not have the aforementioned drawbacks.